Geologic interpretation of seismic reflection profiles on the Continental Shelves of Oregon and Washington is measurably enhanced through the knowledge of Tertiary subsurface stratigraphy penetrated in 10 deep exploration wells drilled in the mid-1960's (Braislin and others, 1971; Snavely and others, 1977). These subsurface data make it possible to relate to the acoustic units differentiated on seismic-reflection profiles to time-stratigraphic units as determined from micropalentontological studies of samples collected from these wells. These biostratigraphic data also permit correlations between time-stratigraphic units in the offshore test wells and between those units and formations penetrated in onshore test wells, as well as strata that crop out in coastal Oregon and Washington.